Device for selecting extreme value of plural input signals

ABSTRACT

A fluid-operated apparatus for selecting extreme magnitudes, that is, the maximum or minimum magnitudes from several input signals, including a housing which is divided into several uniform chambers which are totally closed for the exception of the input thereto. The chambers are separated by flexible diaphragms carrying actuating projections thereon which transmit the pressure signals to the adjacent membranes or diaphragms, the last actuating means producing a signal corresponding to the extreme value present in one of the chambers by releasing such signal from a fluid source.

United States Patent Inventors Appl. No.

Filed Patented Assignee DEVICE FOR SELECTING EXTREME VALUE OF PLURALINPUT SIGNALS 6 Claims, 5 Drawing Figs. [1.8. CI 25l/61.2, 235/201 ME,251/634 Int.Cl Fl6k 31/145 [50] Field oiSearch 251/61, 61.1, 61.2, 61.3,61.4, 61.5; 235/201 ME [56] References Cited UNITED STATES PATENTS3,319,644 5/1967 Thorbum 235/201 X 3,335,950 8/1967 Tal et a1 235/201Primary Examiner-Arnold Rosenthal PATENTEDunv 9 ISYI FIG-1 DEVICE FORSELECTING EXTREME VALUE OF PLURAL INPUT SIGNALS This is a continuationof application Ser. No. 556,655, filed June 10, 1966, now abandoned.

The present invention relates generally to a fluid control apparatus,and more particularly it relates to a device for automatically selectingextreme values from a plurality of fluid signals of different amplitudesand, which is capable of processing such signals into logical functions.

Devices for automatically selecting extreme values from fluid signalsare known. A known such device operates on the principle of powercomparison and employs fixedly tensioned elastic membranes which definechambers in a housing. One of the chambers is adapted to receive theinput signal, whereas the other chamber contains a nozzle or a valve towhich the membrane is mechanically coupled. Such devices may beconnected into a system forming a pneumatic series circuit, requiringthat the chambers which contain the nozzles or the valves be connectedwith each other by pneumatic conduits.

The shortcomings of the above-described known system resides in that thepresence of nozzles and valves requires mechanical coupling between themand the membranes, furthermore the number of the nozzles or valvesshould correspond to the number of the anticipated signals. In view ofthe fact that a large number of nozzles or valves is required to build arelatively simple system, manufacturing costs of such a system are highand its operation, despite the high cost, is unreliable due to thepresence of a large number of valves and nozzles which are bound tobecome clogged after a short time of operation.

' Other devices are also known for processing discrete signals intological combinations, which employ movable parts such as slides orballs, or the like. An example for the last-mentioned known device isthe double return valve which is capable of representing the logicalfunction OR.

1 It is an object of the present invention to provide an improvedfluid-operable device for automatically selecting extreme values from aplurality of fluid signals and which is capable of processing of suchselected discrete signals into logical functions.

It is a further object of the invention to provide a fluidoperabledevice for automatically selecting extreme values from a plurality offluid signals, in which selection of the extreme values is performedsolely by the response of flexible members without employing nozzles orvalves within the operating chambers.

It is still a further object of the invention to provide a fluidoperabledevice capable of processing discrete signals into logical functions byemploying only simple movable elements without nozzles or valves.

In accordance with the invention the apparatus for the selection ofextreme values from a plurality of fluid signals comprises a housing, aplurality of members defining a plurality of successive chambers in thehousing, input means for permitting flow of a signal to each of thechambers, means secured to each of the members and movable therewithupon movement of the associated member in response to a signal presentin a chamber adjacent the associated member for transmitting movement ofone member to an adjacent member, and means responsive to thetransmitting means associated with the member of the last one of thesuccessive chambers for producing an output signal.

The invention provides that the members defining the chambers in thehousing constitute flexible elements, such as membranes. Each of themembranes is mounted for movement axially in either direction inresponse to a pressure signal in the chambers at either side of themembrane, and each membrane has a transmitting means carried therewithwhich is disposed at the side of the associated membrane facing theresponsive means.

In accordance with the invention and in one embodiment thereof, thetransmitting means comprise projections of a predetermined height whichpermit actuation of the responsive means when a signal in any one of thechambers has a magnitude larger than the pressure of the fluid in apneumatic circuit associated with the device, whereby a signal having amaximum value is selected from a plurality of signals of differentmagnitude.

In another embodiment of the invention, the device is made capable toprocess the discrete signals into logical functions by providing amechanical, electrical or optical signal transducer I in cooperationwith the projection of the last membrane associated with the last one ofthe successive chambers, so that if a signal appears in any one of thechambers, the projection will transmit movement of the membraneassociated with the chamber where the signal is present to the membranesof the successive chambers and finally to the transducer, whereupon alogical function of the type "OR is produced, due to the fact that thepresence of a signal in either one of the chambers is capable to actuatethe transducer element.

In another embodiment of the invention the projections transmittingmotion of a membrane to the adjacent membranes are so shaped andarranged that a transducer disposed in cooperation with the projectionassociated with the last membrane of the last chamber of the successivechambers will be actuated only if a signal is present in each of thechambers. Under the last-mentioned circumstances, actuation of thetransducer produces a logical function of the type AND.

In a still further embodiment of the invention the logical function ORis produced in a device in which the flexible membranes are replaced bypistons slidably mounted in the housing and each piston defining achamber within the housing and, carrying a projection similar to theprojections described in connection with the above OR embodiment,whereupon presence of a signal in any one of the chambers will cause theassociated piston to be displaced, which displacement then transmitsmotion to the adjacent pistons, whereby a logical function of the typeOR" is produced at a transducer pin cooperation with the projection ofthe last piston.

The invention will become more readily apparent from the followingdescription of preferred embodiments thereof illustrated in theaccompanying drawing, in which:

FIG. 1 is a schematic showing of a device for selecting the maximum orlargest among a plurality of input signals;

FIG. 2 is a schematic showing of a device, similarly in structure tothat of FIG. 1, for processing discrete signals into 0R" function;

FIG. 3 is a schematic showing of a device for selecting the minimum orthe smallest from a plurality of input signals;

FIG. 4 is a schematic showing of a device similar in structure to thatof FIG. 3, for processing discrete signals into the logical functionAND";

FIG. 5 is a schematic showing of a device for processing discretesignals into OR combinations by means of movably arranged pistons or thelike.

With reference to the drawing in which like elements are designated bythe same reference numerals, and more particularly to FIG. 1, thefluid-operable device for selecting the largest value from a pluralityof input signals includes a housing I in which a plurality of membranes2a, 2b, 2c are mounted and define chambers 6, 7, and 8 in cooperationwith the housing walls. It is understood that any number of membranescould be mounted into the housing, but for illustrative purposes, only adevice including three membranes is shown. Chambers 6, 7, and 8 eachhave an input terminal 9', l0, and. 11, respectively. The membranes 2a.2b and 2c carry projectionlike elements 3, 4, and 5, respectively, whichare adapted to move with their associated membranes in response topressure signals 9, l0 and 1] fed through inputs 9', 10' and II. It isunderstood that the shape of the projections is a matter of choice andit is the height of the projections which should be correlated with thespacing of the adjacent membranes. The housing 1 has in its top wallportion a recess la formed therein, which has the configuration of aprojection associated with any of the membranes and is aligned with thecenterline of the adjacent membrane 2a. The projections serve totransmit motion of the membrane to an adjacent membrane. Motiontransmission by the projections occurs in one preferred direction tooperate a load as hereinafter described, whereas the projections serveto block movement of an adjacent membrane during its movement in theopposite direction.

The housing terminates in a pneumatic circuit portion having a nozzle 12which is aligned with the projection 5 which is last in the successionof the membranes, projection 5 being arranged to cooperate with nozzle12 in a. manner that nozzle 12 may be closed or opened by projection 5under certain conditions hereinafter described. The pneumatic circuitincludes a source 14 of pressurized fluid which through a throttle valve13 flows in the space surrounding the nozzle and into a load circuit(not shown) beyond the nozzle so that an output signal 15 is capable ofbeing developed under certain conditions hereinafter described. Nozzlel2 communicates with a system capable of relieving the pneumatic circuitof pressures when nozzle 12 is not engaged by projection 5, such systempreferably being the atmosphere.

During rest position of the device, as shown in FIG. 1, the outputsignal 15 is zero since projection 5 of the last membrane 2c is out ofengagement with the nozzle 12, therefore, any pressurized fluid flowingfrom source 14 is relieved to the atmosphere through nozzle 12.

The above described extreme value selecting device operates as follows:

Pressure signals 9, 10, 11 are applied to inputs 9, 10, 11' and, forpurposes of illustration, it is assumed that signal 10 is larger thanthe other signals. The output signals must assume the magnitude of thelargest signals among the input signals, which is the magnitude ofsignal 10. Chamber 7 among the uniform chambers will be under thehighest pressure. Membrane 2a deflects upwardly until it engagesprojection la, since the force exerted on membrane 2a from below anddirected upwardly as the result of the pressure in chamber 7, is greaterthan the force exerted on membrane 20 from above, downwardly, andresulting from the pressure in chamber 6 due to the presence of a signal9. Membrane 2b deflects downwardly and in an extent proportional to themagnitude of the pressure in chamber 7. At the same time projection 4presses membrane 2b also downwardly due to the fact that the deflectionof membrane 2b is greater than the deflection of membrane 20 resultingfrom the sole effect of the pressure of signal 11 in chamber 8.Projection 5 will, therefore, cover nozzle 12. As a result, the fluidmaterial coming from source 14 cannot escape to the atmosphere. Thepressure chamber 30 exerts a force on the bottom of membrane 20. Thismembrane is, therefore, pressed somewhat upwardly and projection 5 isdisplaced somewhat from nozzle 12, so that a portion of the fluidmaterial may escape now to the atmosphere over nozzle 12. As a result ofthis, the pressure of chamber 30 exerted against the bottom of membrane20 will become less and less and projection 5 will again move closer tonozzle 12. The result is that a balanced condition will set in betweenthe force which moves membrane 20 through the medium of projection 5downwardly and between the force resulting from the pres sure in chamber30 against membrane 2c upwardly. Therefore, the output signal will havea magnitude which will equal the magnitude of the largest input signalwhich, in the illustrating example, is the magnitude of signal 10. Thepressure of source 14 must be always larger than the pressure of thelargest input signal.

When the magnitude of signal 10 decreases, but it is still larger thanany of the other input signals 9, 11, then the gap existing betweenprojection 5 and nozzle 12 in the balanced state will become somewhatlarger, and as a result of which, a larger portion of the pressurizedmaterial coming from source 14 will escape to the atmosphere. Therefore,signal 15 is again as large as the largest input signal, which is stillsignal 10.

The present selecting arrangement requires no adjustment or calibration.It is, however, advisable that projections 3, 4 and 5 should be madewith a height that they in the inopera tive position nearly engage theadjacent membranes so that their membranes do not require excessivedeflection during operation.

The device shown in FIG. 2 is similar in structure to the device of FIG.1, with the exception that the pneumatic circuit comprising the source14, the throttle valve 13 and nozzle 12, is replaced by a transducer 16which might be of an electrically operated device, an optical device ora mechanical plunger. A signal appearing at any of the inputs 9', 10' or11' will produce a movement of the membranes in a direction of the arrowwhereupon the projection 17 of the transducer will be' engaged byprojection 5 of the last membrane 20, resulting in the production of alogical function of the type 011"; since actuation of the transducer wasdue to the presence of a signal in any one of the chambers.

With reference to FIG. 3, the device shown therein represents anapparatus capable of detecting the presence of a signal the magnitude ofwhich is smaller than any of the signals present in the other chambers.To this effect, the device includes a plurality of membranes which aredesignated by the same reference numerals as those in FIGS. 1 and 2 andwhich carry at one side thereof projection 21, 22 and 23 which aredisposed on the side of the respective membranes facing the nozzle 12 ofthe associated pneumatic circuit hereinafter described. The membranes ontheir opposite sides carry spacing elements 18, 19 and 20. Spacingelement 18 upon deflection of the membrane, cooperates with the wall ofhousing 1 whereas spacing elements 19 and 20 cooperate with theprojections 21 and 22, respectively. The device of this embodimentincludes a pneumatic circuit in which like elements are designated bythe same reference numerals as in the pneumatic circuit of FlG. 1,namely a source of pneumatic pressure 14 supplying fluid throughthrottle valve 13 into the space surrounding nozzle 12 and furthercontinuing into a load (not shown). The nozzle 12, similarly asdescribed in connection with the embodiment of FIG. 1 communicates thepneumatic circuit with a relieving system, such as preferably theatmosphere, when not engaged by projection 23. During an illustrativemode of operation of the device one may assume that one of the inputsignals, say 10, is smaller than the signal in any one of the otherchambers of the device, whereupon membrane 2a deflects inwardly intochamber 7, and membrane 2b also deflects inwardly into chamber 7.

When the pressure in chamber 6 is larger than the pressure in chamber 7,as has been described above and the pressure in chamber 8 is larger thanthe pressure in chamber 7, membrane 2b deflects upwardly while membrane20 will deflect downwardly. As a result, the nozzle 12 will be coveredby projection 23 and a pressure will build up in chamber 30. Thispressure presses the membrane 20 upwardly, whereby also membrane 212will be able to deflect upwardly. A balanced state will be attained whenthe pressure in chamber 30 is equal to the lowest pressure in any one ofthe chambers 6, 7 or 8, which in the illustrative example is thepressure in chamber 7. As a result, the magnitude of the output signal15 will be equal to the magnitude of the smallest of the input signals.Also here, the pressure of source 14 must be larger than the pressure ofthe largest input signal in order that a force compensation could beperformed so that the output signal could be made equal to the smallestof the input signals.

FIG. 4 is structurally similar to the embodiment of FIG. 3, thereforelike elements which are similar to the abovedescribed embodiments and tothe one described in FIG. 3, will be designated by like referencenumerals. In this embodiment, like in the embodiment shown in FIG, 2,the device dispenses with the pneumatic circuit and instead has atransducer 16 disposed in cooperation with the last projection 23, sothat movement of projection 23, will actuate transducer 16 which mightbe an electrical device, optical apparatus or a mechanical plunger. Inview of the description in connection with the embodiment of FIG. 3, itbecomes clear that the device of FIG. 4 in order to operate as a logicalconverter, should have signals present at all inputs, that is, in allchambers, to cause movement of projection 23 downwardly so that alogical function of the type AND could be obtained upon movement of thetransducer in the direction of the arrow.

With reference to the embodiment shown in FIG. 5, the housing 1 includesa plurality of pistonlike elements 24, 25 and 26 which slide influidtight relationship with the walls of the housing so that eachpistonlike element defines within the housing a chamber similarly likethe membranes in the abovedescribed embodiments. Each of the chambersincludes an input 9', 10' and 11', respectively. The pistonlike elementscarry projections 27, 28 and 29 for transmitting motion between eachother. The pistonlike elements 24, 25 and 26 are adapted to slide in thehousing over a distance corresponding to the distance between therespective inputs and are guided fluidtight in the housing by means, notshown in the drawing. The arrangement of the embodiment is such thatpresence of a signal at any one of the inputs, that is in any one of thechambers, will cause a movement of the pistonlike elements downwardly inthe direction of the arrow, so that transducer 16 will be disposed incooperating relationship with the last projection 29 and engaged andmoved by such projection, whereupon a logical function of the type OR isproduced by the transducer element 16 which might be of the electrical,optical or mechanical type.

It is seen that the invention provides a simplified device for selectingextreme values from among a plurality of signals having differentmagnitudes and devices which are capable of converting pneumatic signalsof the above-mentioned type into logical combinations of the type ANDwithout employing movable elements like valves, whereupon the operationof the device is made more reliable and more economical.

Although the invention has been described with reference to specificembodiments thereof, it is not intended that the invention should belimited to such specific embodiments only, but it should be defined bythe scope of the appended claims.

We claim:

1. Apparatus operable with a fluid for the selection of the one of aplurality of fluid input signals that has an extreme magnitude withrespect to the other signals, comprising a housing, a plurality ofunbiased movable pressure-responsive sealing wall members defining aplurality of uniform successive input chambers in said housing, each ofsaid wall members being individually supported in said housing, separatetransmitting means secured to each of said wall members and movabletherewith upon movement of the associated wall member in response to asignal present in a chamber adjacent said associated wall member fortransmitting movement of one member solely in one direction to anadjacent member, each said transmitting means being secured to only onewall member, and means responsive to the transmitting means associatedwith the member of the last one of said successive chambers forproducing an output signal, wherein each said wall member is mounted formovement axially in either direction in response to a pressure signal inchambers at either side of said wall member, each of said transmittingmeans being disposed at the side of the associated wall member facingsaid responsive means, wherein each of said transmitting means ismounted for movement to exert a force on the next adjacent wall memberonly if there is a pressure difference between said adjacentchambers,'whereby said output signal is produced by the pressure in thatchamber which has an extreme value of pressure with respect to thepressure in the other chambers.

2. Apparatus as claimed in claim 1, wherein said transmitting means areprojections of a predetermined height permitting actuation of saidresponsive means by a signal in any one of said chambers which has amagnitude larger than the signals in the other of said chambers, wherebythe signal having the greatest magnitude is selected from said pluralityof input signals.

3. Apparatus as claimed in claim 1, wherein said responsive meanscomprises a pneumatic circuit including a source of pressurized fluid,nozzle means disposed in cooperating relationship with the transmittingmeans associated with the wall member of said last chamber and adaptedto be sealed by said transmitting means when engaged thereby, saidnozzle means relieving saidpneumatic circuit from pressures of saidsource when not engaged by said transmitting means, and an outputterminal for conveying said pressurized fluid to a load means.

4. Apparatus as claimed in claim 1, wherein each of said wall memberscomprised a piston having said transmitting means disposed thereon, saidtransmitting means comprising projections of a predetermined heightpermitting actuation of said responsive means in response to a signal inany one of said chambers, whereby an OR signal is produced by saidresponsive means.

5. Apparatus as claimed in claim 1, wherein said responsive means isactuated when a signal is present in any of said chambers, whereby anOR" signal is produced by said responsive means.

6. A fluid-operable device for providing an output corresponding to themagnitude of an input fluid signal having an instantaneously extrememagnitude with respect to a plurality of input fluid signals, saiddevice comprising a housing, a plurality of parallel unbiased flexiblemembers individually supported within said housing and defining aplurality of separate successive uniform input chambers within saidhousing, an input signal port extending through said housing to each ofsaid chambers, force transmitting means affixed to said flexible membersfor transmitting movement between said flexible members in response todifferences in magnitude of input signals applied to said ports, saidforce transmitting means comprising separate projections affixed to saidflexible members, each projection extending in the same direction towardan adjacent flexible member and being unattached to the respectiveadjacent member, each said projection being mounted to exert a force inonly one direction on the adjacent flexible member, and means responsiveto movement of the flexible member of the last one of said successivechambers for producing an output signal, whereby said output signal isproduced only in response to that input signal which has an extrememagnitude with respect to the other input signals.

1. Apparatus operable with a fluid for the selection of the one of aplurality of fluid input signals that has an extreme magnitude withrespect to the other signals, comprising a housing, a plurality ofunbiased movable pressure-responsive sealing wall members defining aplurality of uniform successive input chambers in said housing, each ofsaid wall members being individually supported in said housing, separatetransmitting means secured to each of said wall members and movabletherewith upon movement of the associated wall member in response to asignal present in a chamber adjacent said associated wall member fortransmitting movement of one member solely in one direction to anadjacent member, each said transmitting means being secured to only onewall member, and means responsive to the transmitting means associatedwith the member of the last one of said successive chambers forproducing an output signal, wherein each said wall member is mounted formovement axially in either direction in response to a pressure signal inchambers at either side of said wall member, each of said transmittingmeans being disposed at the side of the associated wall member facingsaid responsive means, wherein each of said transmitting means ismounted for movement to exert a force on the next adjacent wall memberonly if there is a pressure difference between said adjacent chambers,whereby said output signal is produced by the pressure in that chamberwhich has an extreme value of pressure with respect to the pressure inthe other chambers.
 2. Apparatus as claimed in claim 1, wherein saidtransmitting means are projections of a predetermined height permittingactuation of said responsive means by a signal in any one of saidchambers which has a magnitude larger than the signals in the other ofsaid chambers, whereby the signal having the greatest magnitude isselected from said plurality of input signals.
 3. Apparatus as claimedin claim 1, wherein said responsive means comprises a pneumatic circuitincluding a source of pressurized fluid, nozzle means disposed incooperating relationship with the transmitting means associated with thewall member of said last chamber and adapted to be sealed by saidtransmitting means when engaged thereby, said nozzle means relievingsaid pneumatic circuit from pressures of said source when not engaged bysaid transmitting means, and an output terminal for conveying saidpressurized fluid to a load means.
 4. Apparatus as claimed in claim 1,wherein each of said wall members comprise a piston having saidtransmitting means disposed thereon, said transmitting means comprisingprojections of a predetermined height permitting actuation of saidresponsive means in response to a signal in any one of said chambers,whereby an ''''OR'''' signal is produced by said responsive means. 5.Apparatus as claimed in claim 1, wherein said responsive means isactuated when a signal is present in any of said chambers, whereby an''''OR'''' signal is produced by said responsive means.
 6. Afluid-operable device for providing an output corresponding to themagnitude of an input fluid signal having an instantaneously extrememagnitude with respect to a plurality of input fluid signals, saiddevice comprising a housing, a plurality of parallel unbiased flexiblemembers individually supported within said housing and defining aplurality of separate successive uniform input chambers within saidhousing, an input signal port extending through said housing to each ofsaid chambers, force transmitting means affixed to said flexible membersfor transmitting movement between said flexible members in Response todifferences in magnitude of input signals applied to said ports, saidforce transmitting means comprising separate projections affixed to saidflexible members, each projection extending in the same direction towardan adjacent flexible member and being unattached to the respectiveadjacent member, each said projection being mounted to exert a force inonly one direction on the adjacent flexible member, and means responsiveto movement of the flexible member of the last one of said successivechambers for producing an output signal, whereby said output signal isproduced only in response to that input signal which has an extrememagnitude with respect to the other input signals.